Barrier

You form a shimmering force field around the target.

Reaction trigger: Just before either you or a creature within range takes damage.

Effect: Create a shield that grants the target temporary HP equal to 2d6 + your spellcasting modifier. While this spell is in effect, the shield absorbs all of the damage that they would have taken. This spell ends when the shield loses all of its HP or if the creature suffers a critical hit, in which case, the barrier does not absorb any of the damage.

At Higher Levels: The shield HP increases by 1d6 for each spell level increase. If you cast this spell at 3rd Level or higher, you can instead cast this as an Area Barrier in response to an effect that deals area damage. In this case, the spell is Instantaneous, you do not grant temporary HP to any creature, and you instead reduce the damage of an area effect spell or ability against all creatures within a 4m radius Sphere.

A mage's best friend to protect allies.